1) Renamed dir_walk.rb to file_scanner.rb

2) Updated file_scanner.rb to file dir paths and output Mp3Tag information.

3) Update cli.rb to reflect renaming of dir_walk.rb
1) Renamed dir_walk.rb to file_scanner.rb

2) Updated file_scanner.rb to file dir paths and output Mp3Tag information.

3) Update cli.rb to reflect renaming of dir_walk.rb
Merge branch 'feature/list_mp3_files' into develop